The present invention concerns new granules of anhydrous aluminum chloride and a procedure to produce these granules.
Aluminum chloride is often used as a catalyst in organic chemistry and also in the cosmetics industry. In the course of its manufacture, the aluminum chloride is obtained in the gaseous phase, possibly mixed with other products, and it is isolated by condensing it on a cold surface at ambient temperature. One thus obtains a crust of aluminum chloride which is detached from the surface by mechanical means such as vibrations or impact. The cold surface is simply the internal wall of a steel container exposed to the ambient air.
The crusts of aluminum chloride are crushed in order to obtain a product whose pieces of various shapes are smaller than 5 cm in their largest dimension. The crushing also produces dust and it is necessary to screen the aluminum chloride and recycle the fines. Japanese patent applications No. 34988/70 and 34989/70 of May 18, 1970, describe a procedure for isolating aluminum chloride in the gaseous phase consisting of causing the gas to pass over a surface kept at 80.degree. or 85.degree. C., then when the aluminum chloride has formed crystals, this surface is heated to 220.degree. C. in order to detach the aluminum chloride which is recovered. Often these crystals, at the time of their formation and growth, have a tendency to stick to each other and to form a crust which it is necessary to crush and screen.
New granules of aluminum chloride have now been found which are characterized by the fact that they have essentially the shape of a cone.